Potassium Carbonate → 3,10-Difluoro-13,14-bis-pyrrolidin-2-ylmethyl-6,7-dihydro-pyrazino[1,2-a;4,3-a']diindole

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Reaction Conditions

Reaction Steps

A mixture containing 28 (1.94 g, 2.97 mmol) and K2CO3 (2.05 g, 14.8 mmol) in MeOH (60 mL) was heated at 60° C. for 1.5 h. The reaction mixture was cooled to ambient temperature and diluted with EtOAc and water. The layers were separated and the aqueous phase was extracted three times with EtOAc. The combined organic extracts were washed with brine, dried over anhydrous Na2SO4, filtered, and concentrated to afford 1.57 g (quant.) of 29 as a yellow solid which was used without further purification. TLC analysis, 1:1 hexane/EtOAc, Rf(28)=0.9; Rf(29)=0.01. 1H NMR (CDCl3, 300 MHz) δ7.65 (m, 1H), 6.98 (app d, J=8.2 Hz, 1H), 6.90 (app t, J=8.3 Hz, 1H), 4.31 (s, 2H), 3.97 (br s, 3H), 3.54 (m, 1H), 3.31 (m, 1H), 3.14 (m, 1H), 2.97 (m, 1H), 1.83 (m, 1H), 1.68 (m, 2H), 1.42 (m, 1H) ppm. 13C NMR (CDCl3, 75 MHz) δ160.6 (d, JC-F=238.7 Hz), 136.2 (d, JC-F=12.0 Hz), 127.1, 125.4, 120.8 (d, JC-F=10.2 Hz), 109.8, 108.9 (d, JC-F=24.6 Hz), 95.3 (d, JC-F=26.3 Hz), 59.6, 45.6, 41.6, 31.0, 30.7, 24.5 ppm.

Provenance & Evidence